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help / color / mirror / Atom feedFrom: Chao Li <[email protected]>
To: [email protected]
Cc: Tom Lane <[email protected]>
Subject: Re: Improve hash join's handling of tuples with null join keys
Date: Wed, 13 Aug 2025 09:16:01 +0000
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
<[email protected]>
I downloaded the patch and tested all join types: inner, left, right, full, semi and anti. Basically my tests all passed. However, I didn't test any case of parallel query.
I have two nit comments:
1. In hashjoin.h, line 76-78, the added comment says "(In the unlikely but supported case of a non-strict join operator, we treat null keys as normal data.)". But I don't see where non-strict join is handled. So, how this patch impact non-strict joins?
2. Two new join states are added: HJ_FILL_OUTER_NULL_TUPLES, HJ_FILL_INNER_NULL_TUPLES. There are existing join states: HJ_FILL_OUTER_TUPLE and HJ_FILL_INNER_TUPLES. They all use "FILL". But I think that "FILL" in HJ_FILL_OUTER_NULL_TUPLES means different from in "HJ_FILL_OUTER_TUPLE". Because HJ_FILL_OUTER_TUPLE means that when returning an outer tuple, it needs to fill in null-extension of inner tables; while HJ_FILL_OUTER_NULL_TUPLES means to return outer tuples that have null join keys. I would suggest something like "APPEND" for the new states: HJ_APPEND_OUTER_NULL_TUPLES and HJ_APPEND_INNER_NULL_TUPLES.
The new status of this patch is: Waiting on Author
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To: [email protected]
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Subject: Re: Improve hash join's handling of tuples with null join keys
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